With the development of technology and the increasing market demands, high performance synthetic materials have been used since they have been invented in areas like aviation, aerospace, military, electronics, mechanical industry and other industries requiring safe and light materials. High performance synthetic material—aramid fiber paper—emerges at a historic moment and, has high strength, low deformability, resistance to high temperature, resistance to chemical corrosion, no fatigue reaction and excellent insulation property. Chinese Patent No. 99114635.2 discloses a synthetic fiber paper made of poly(p-phenylene terephthal amide) fibre (also named as aramid fiber 1414, Fanglun 1414 or PPTA) as main fiber and polyester fiber (polyethylene glycol terephthalate fiber) as crosslinking fiber, which has some advantages of high temperature resistance, high strength, low deformability and etc. However, the invention is not good enough in papermaking performance and finished paper performance. First, during the papermaking of the paper blank, the strength of the paper blank is poor and the defective index of the papermaking is high. Second, after hot rolling, the paper sheets have insufficient density (tightness), high porosity and high permeability, and the penetration of glue stuff is difficult to control while manufacturing honeycomb board. Third, the hot strength retention of the honeycomb paperboard is not good enough.
Chinese patent application CN1570271 discloses a synthetic paper containing carbon fiber and aramid fiber and a wet papermaking process, wherein carbon fibre and aramid fiber are used as structural fiber, and polyester or polyphenyl thioether fiber is used as crosslinking fiber. Due to the presence of carbon fiber, this synthetic fiber paper tends to be used with respect to heat transmission and electric conduction, and its electric insulation and heat insulation properties are not good enough.
Both Chinese patent application No. 2006100633513.2 entitled SYNTHETIC FIBER PAPER CONTAINING BASALT FIBER AND ARAMID FIBRE AND PREPARATION METHOD THEREOF and Chinese patent application No. 200610063595.0 entitled SYNTHETIC FIBER PAPER CONTAINING POLYPHENYL THIOETHER AND CHEMICAL FIBER AND PREPARATION METHOD THEREOF disclose a method of preparing synthetic aramid fiber paper using polyphenyl thioether fiber as crosslinking fiber, wherein only aramid fiber is used as stuffing material, and the resultant paper sheets are confronted with high porosity and excessive permeability.
In the above-mentioned processes for preparing synthetic paper using aramid fiber 1414, a hot melt fiber such as polyester or polyphenyl thioether is used as crosslinking fiber. This produces an effect of point bonding, resulting in many cavities among the fibers, loose structure of the paper sheets, and unmanageable penetration of the resin while manufacturing honeycomb board. Moreover, when a high amount of polyester is used, the hot strength retention of the honeycomb board fails to reach a desired result.